published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis--Ph. D., University of Hong Kong, 1986.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 235-242).

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (November 14, 2006) Vita. Includes bibliographical references.

3,4,6-Tri-0-acetyl-D-glucal (1) reacted with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl to yield a mixture of two epimeric anhydrodeoxyheptitols, namely, 4,5,7-tri-0-acetyl-2,6-anhydro-3-deoxy-D-manno-heptitol (2) and 4,5,7-tri-0-acetyl-2,6-anhydro-3-deoxy-D-gluco-heptitol (3). De-0-acetylation of the mixture, followed by chromatographic separation, yielded 2,6-anhydro-3-deoxy-D-manno-heptitol (4) and 2,6-anhydro-3-deoxy-D-gluco-heptitol (5). Compounds (4) and (5) were oxidised with periodate to yield dialdehydes which on reduction with sodium borohydride afforded enantiomeric tetrol ethers. Reaction of 3,4,6-tri-0-acetyl-D-glucal (1) with carbon monoxide and deuterium, followed by de-0-acetylation and chromatographic separation gave 2,6-anhydro-5-deoxy-D-manno-heptitol-1,1,3-²H3(cis)(6) and 2,6-anhydro-3-deoxy-D-gluco-heptitol-1, 1,3-²H3(cis) (7) . Examination of the proton magnetic resonance spectra of the normal (4,5) and deuterated anhydrodeoxy heptitols (6,7) revealed their structures and showed that cis-addition of carbon monoxide and hydrogen to the double bond of (1) had taken place. Reaction of the mixture of partially acetylated heptitols (2) and (3) with p-toluenesulphonyl chloride followed by fractional crystallisation of the products gave pure 4,5,7-tri-0-acetyl-2,6-anhydro-3-deoxy-1-0-(p-toluenesul-phonyl)-D-gluco-heptitol (8). Similarly,, the mixture of (2) and (3) reacted with p-bromobenzenesulphonyl bromide to give 4,5, 7-tri-0-acetyl-2,6-anhydro-1-0-(p-bromobenzenesulphonyl)-3-deoxy-D-gluco-heptitol (11), the structure of which was confirmed by X-ray structure analysis by A. Camerman and J. Trotter. Therefore, the absolute structures of compounds (4) and (5) were ascertained. Compounds (8) and (11) were converted to (5) by a series of reactions. Comparison of the exchange reaction of sodium iodide with 4,5,7-tri- 0-acetyl-2,6-anhydro-3-deoxy-1-0-(p-toluenesulphonyl)-D-gluco-heptitol (8) and with 4,5,7-tri-0-acetyl-2,6-anhydro-3-deoxy-1-0-(p-toluenesulphonyl)-D-manno-heptitol (14) revealed that the equatorial primary p-toluenesulphonoxy group of (8) was exchanged more readily than that of (14). The hydroformylation of (1) yielded two enantiomeric aldehydes (16a, 16b) which were separated chromatographically via their 2,4-dinitrophenyl-hydrazones (16b) and (17b). Both (16b) and (17b) were degraded to (4) and (5), respectively. 3,4-Di-0-acetyl-D-arabinal (18) reacted with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl to yield, upon de-0-acetylation and chromatographic separation, a mixture of two epimeric anhydro-deoxyhexitols, namely, 1,5-anhydro-4-deoxy-L-ribo-hexitol (21) and 1,5-anhydro-4-deoxy-D-lyxo-hexitol (22). Compounds (21) and (22) were converted into enantiomeric 2-deoxy-3-0-(2-hydroxyethyl)-L-glycero-tetritol (23) and 2-deoxy-3-0-(2-hydroxyethyl)-D-glycero-tetritol (24). Compound (23) was identical to an authentic sample of 2-deoxy-3-0-(2-hydroxyethyl)-L-glycero-tetritol. 1,2,4,6-Tetra-0-acetyl-3-deoxy-α-D-erythro-hex-2-enopyranose (29) reacted with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl to yield 1,2,3¹,4,6-penta-0-acetyl-3-deoxy-3-C-(hydroxymethyl)-α-D-gluco-pyranose (31) besides hydrogenolysed hydrohydroxymethylated products, a similar reaction of (29) with deuterium instead of hydrogen gave 1,2,3¹,4,6-penta-0-acetyl-3-deoxy-3-C- (hydroxymethyl) -α-D-gluco-pyranose-2,3¹,3¹ -²H3 (cis) (33). The structures of (31) and (33) were established by p.m.r. spectroscopy. 2,3,4,6-Tetra-0-acetyl-α-D-glucosyl bromide (26) reacted with sodium tetracarbonylcobaltate under compressed carbon monoxide followed by treatment with triphenylphosphine to afford 2,3,4,6-tetra-0-acetyl-β-D-glucosyl tri-carbonyl triphenylphosphine cobaltate (39) and 3,4,5,7-tetra-0-acetyl-2,6- anhydro-D-glycero-D-gulo-heptosoyl tricarbonyl triphenylphosphine cobaltate (41). Reduction of. (39) and (41) with sodium borohydride followed by acetylation gave 2,3,4,6-tetra-0-acetyl-1,5-anhydro-D-glucitol (40) and 1,3,4,5,7-penta-0-acetyl-2,6-anhydro-D-glycero-D-gulo-heptitol (42). Both (40) and (42) were compared with authentic samples and shown to be the same. / Science, Faculty of / Chemistry, Department of / Graduate

Methyl 2,3-anhydro-4,6-0-benzylidene- α-D-mannopyranoside was allowed to react with carbon monoxide and methanol in the presence of dicobalt octacarbonyl at elevated temperatures and pressures. The resulting product mixture contained unreacted epoxide, methyl 3-0-methyl-α -D-altropyranoside and methyl 4,6-0-benzylidene- α-D-altropyranoside. Methyl 2,3-anhydro-4,6-0-benzylidene- α-D- mannopyranoside was allowed to react with carbon monoxide (990 p.s.i.) and hydrogen (910 p.s.i.) in the presence of dicobalt octacarbonyl at 140°. The resulting product mixture contained two products. The n.m.r. indicated that the epoxide ring had not been opened. In one product, the benzylidene ring was completely removed and in the other component the benzylidene ring had been partially altered. When Brigl's anhydride was allowed to react with carbon monoxide (910 p.s.i.) and hydrogen (990 p.s.i.) in the presence of dicobalt octacarbonyl at 106° for 30 minutes, the resulting product mixture contained one major product and two minor products. The minor product was presumed to be a sugar and the major product (75-80%) had been characterized as 2,6-anhydro-D-glycero-D-gulo-heptitol. / Science, Faculty of / Chemistry, Department of / Graduate

Hydroformylation of 5,6-anhydro-1,2-0-isopropylidene-α-D-glucofuranose (XXIV) with carbon monoxide (70 atm.) and hydrogen (70 atm.) at a temperature of 100-105° C. gave 6-deoxy-1,2-0-i sopropylidene-α-D-gluco-heptodialdo-1,4-furanose-3,7-pyranose (XXV) in 78% yield. Minor quantities of the rearrangement product, 6-deoxy-5-keto-1 ,2-0- i sopropyl i dene-α-D-gl ucofuranose (XXVI), and the hydro-hydroxymethyl at i on product, 6-deoxy-1 ,2-0- isopropyl idene-α-D-gl uco-hepto-1 , 4-furanose (XXVI I), were isolated in 9% and 4% yields, respectively. Acetylation of crude (XXV) afforded two anomeric derivatives (XXIX, XXVII I). Under identical experimental conditions, 5 ,6-dideoxy-1 , 2-0-isopropyl idene-α-D-xylo-hex-5-enofuranose (XXXIII) gave 5,6-dideoxy-α-D-xylo-heptodialdo-1 ,4-furanose-3,7-pyranose (XXXIV) in 51% yield. A minor amount of 5,6-dideoxy-α-D-xy1ohepto-1,4-furanose (XXXV) in about 5% yield was also detected by thin layer chromatography (T.L.C.) Fusion of 5 ,7-di-0-acetyl-6-deoxy-1,2-0-isopropylidene-α-D-gluco-heptodialdo-1,4-furanose-3,7-pyranose (XXVIII) with 5,6-dimethyl-benzimidazole using chloroacetic acid as a catalyst at 170-175°C. gave two anomeric nucleosides 1-(3'-0-acetyl-2'-deoxy-6’,7'-0-isopropylidene heptodialdo-4’,7'-pyrariose-α(and β-)-L-gulopyranosyl) -5,6-dimethyl -benzimidazole (XXXVII, XXXVIII) in 42% yield. These nucleosides were separated by multiple ascending development on preparative T.L.C. plates of silica gel G. impregnated with 2% G.E.Phosphor. Assignment of structures of the nucleosides was based on an analysis of their N.M.R. spectra. / Science, Faculty of / Chemistry, Department of / Graduate

La compréhension du comportement des actinides dans l’environnement est un enjeu important et très complexe en raison des nombreux phénomènes intervenant dans les processus chimiques. Parmi eux, nous pouvons citer la complexation, notamment via les fonctions carboxylates issues des substances humiques présentes dans les sols. En milieu aqueux, les actinides au degré d’oxydation IV sont très sensibles à l’hydrolyse impactant alors leur mobilité. Au cours de ce travail de thèse, nous avons étudié la réactivité de ces actinides(IV) (Th, U et Np) en présence de ligands organiques de type carboxylate aromatique, afin d’enrichir nos connaissances sur les entités formées. Plus de quarante nouveaux composés à base d’actinides(IV) et d’acides polycarboxyliques ont été synthétisés. Leurs structures cristallographiques ont été déterminées par DRX sur monocristal et leurs descriptions sont rapportées. Le contrôle de l’hydrolyse de ces métaux au sein de nos composés a été effectué par une variation de l’acidité en milieu aqueux ou par ajout contrôlé de quantités d’eau dans des solvants organiques. Certains des composés présentés sont construits autour d’assemblages polynucléaires possédant entre 2 et 38 centres métalliques. Pour ces derniers ({U38} et {Np38}), une nouvelle voie de synthèse a été investiguée. Au cours de l’étude de ces différents composés, nous avons mis en évidence les analogies ou les différences existant entre ces actinides, et avons enrichis notamment nos connaissances sur la cristallochimie du neptunium(IV). Enfin, nous avons montré la capacité de ligands N- et O- donneurs à complexer simultanément l’uranium(IV) avec d’autres métaux di- (Mn) ou trivalent (Ln). / Understanding the behavior of actinides in the environment is an important and very complex issue due to phenomena involved in chemical processes. Among them, one can mention the complexation, via carboxylate functions from the humic substances present in the soils. In an aqueous medium, actinides at the oxidation state IV are very sensitive to the hydrolysis process impacting their mobility. This thesis focuses the reactivity of these actinides (IV) (Th, U and Np) in the presence of organic ligands with aromatic carboxylate functions, in order to improve our knowledge about entities formed and linked to such organic linkers.More than forty new compounds based on actinides (IV) and polycarboxylic acids have been synthesized. Their crystallographic structures were determined by single crystal XRD and their descriptions are reported. The control of the hydrolysis of these metals within our compounds has been managed by varying the acidity in aqueous medium or by addition of controlled amount of water in organic solvents. Some of the compounds presented are built from polynuclear moieties having from 2 to 38 metal centers. For the latter ({U38} and {Np38}), a new synthetic pathway was investigated. During the study of these different compounds, we have demonstrated the analogies or the differences existing between these actinides, and have improved our knowledge on the crystallochemistry of neptunium (IV). Finally, we proved the ability of N- and O-donor ligands to simultaneously complex the uranium (IV) with other di- (Mn) or trivalent (Ln) metals.

yes / Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, “Pacman” geometry that stabilizes the UV oxidation state and promotes chemistry at a single uranyl oxo-group. We present here new and straightforward routes to singly reduced and oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both oxo-groups are Mg functionalized as a result of Mg−N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U−O−Zn dative interactions, leading to reductive silylation of the uranyl oxo-group in preference to metalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or silylation of the exo-oxogroup.